1. Field of the Invention
The present invention relates to a sanitary napkin with a projection disposed on a body surface of a napkin body and more particularly to a sanitary napkin whose projection can easily conform to the vaginal opening, the anus, and the intergluteal cleft so as to be effective in preventing leakage of menstrual blood.
2. Description of the Related Art
There have been known sanitary napkins with a napkin body containing a liquid-absorbent layer and a projection projecting from a body surface of the napkin body.
Japanese Unexamined Patent Application Publication No. 2001-504727 discloses a sanitary napkin in which a topsheet is disposed on a body surface of a liquid-absorbent layer, and an absorbent body and a stiffening element are interposed between the liquid-absorbent layer and the topsheet. The topsheet, the absorbent body, and the stiffening element form a hump having a generally triangular cross section.
Japanese Unexamined Patent Application Publication No. 2002-301097 discloses an absorbent article in which an absorbent body is disposed between a surface material and a backsheet. At its rear part, the absorbent article has a fold which can easily be deformed to project and fit in the intergluteal cleft of the wearer's body. The fold may be formed by embossing the absorbent body or folding the surface material in two. Providing an elastic member at the fold facilitates projection of the absorbent core or the surface material.
Japanese Unexamined Patent Application Publication No. 2002-320638 discloses a sanitary napkin in which a T-section three-dimensional wall formed of a liquid-permeable sheet is disposed on the body surface of the napkin body. This three-dimensional wall has elastic members for exerting a longitudinal contractive force and is raised from the body surface of the napkin body when the napkin body is curved with front and rear edges of the napkin body being drawn closer to each other by the elastic members.
Since the hump of the sanitary napkin disclosed in the Patent Publication No. 2001-504727 is constructed by interposing the absorbent body and the stiffening element between the liquid-absorbent layer and the topsheet, it is difficult to deform the hump to decrease the distance between two side wall portions. Therefore, the hump cannot easily fit in a deep cleft having a small opening angle such as intergluteal cleft. This tends to result in a clearance between the cleft and the hump, allowing menstrual blood to flow down the intergluteal cleft and causing rearward leakage such as during sleep. Moreover, the absorbent body and the stiffening element within the hump resist concave deformation of the sanitary napkin. Therefore, when worn in the crotch, the sanitary napkin tends to feel uncomfortable and leave a space between the rear part of the sanitary napkin and the wearer's body.
In the absorbent article disclosed in Patent Publication No. 2002-301097, the fold is provided in the rear part of the absorbent article so that it can easily fit in the intergluteal cleft. However, if the fold is formed by processing the absorbent core, it is difficult to project the fold with an acute angle, and therefore, the fold cannot easily fit in a narrow cleft such as the intergluteal cleft. If the fold is formed by folding the surface material in two, on the other hand, the fold becomes less resistant to a lateral compressive force. Therefore, the fold cannot easily follow the movement of the wearer's body, which makes it difficult to keep the fold in contact with the intergluteal cleft.
Since the three-dimensional wall disclosed in the Patent Publication No. 2002-320638 has a T-shaped section, it has the advantage that the liquid-permeable sheet of the three-dimensional wall can easily be kept in contact with the vaginal opening, but it is difficult to fit the central portion of the three-dimensional wall into a deep cleft having a small opening angle such as the intergluteal cleft.